Contact lenses are commonplace today. Most individuals with average refractive errors can quickly and easily acquire and use these lenses in place of prescription eye glasses. For presbyopic individuals, designers have attempted to develop "pinhole" contact lenses. These lenses endeavor to utilize the known theories of pinhole imaging, commonly understood in optics as a method to reduce visual deficiencies. Pinhole mask intraocular lenses also exist for cataract patients (e.g., U.S. Pat. No. 4,955,904 issued to Atebara et al.). A pinhole mask lens conventionally has a clear aperture of up to 4 millimeters in diameter. The annular mask lenses are generally characterized as having a sharp demarcation at the inside and outside edges of the annular mask.
The prior art has focused on the use of "pinhole" contacts for presbyopic individuals (e.g., PCT Publication No. WO 95/08135 published Mar. 23, 1995). However, there is a long felt need for treatment of patients with optical aberration problems, for example, night myopia, which is an increase in refractive error due to the dilation of the pupil and the effect of spherical aberration. Also, increased spherical aberration in patients having radial keratotomy and photo-refractive keratectomy due to prolate geometry of the cornea following surgery and aberrations due to corneal distortion and scarring resulting from trauma or genetic conditions including keratoconus. Conventional pinhole contact lens can not adequately address these problems because the loss of retinal illumination due to the pinhole aperture offsets the peripheral distortion benefit.